1. Field of the Invention
The present invention relates to drum deheading devices and associated systems involving containments for receiving materials from said drums. The invention has particular applicability to the removal of covers on chutes or pits or other containments for receiving coke from coke drums and is particularly suited for association with apparatuses and methods for remote deheading of coke drums.
2. Brief Description of Relevant Art
In the typical delayed coking process, high boiling petroleum residues are fed to a large upright vessel called a coke drum, where they are thermally cracked into light products and a residue, petroleum coke. This residue varies in consistency depending on the quality and composition of feedstock. The coke may be solid, spongy, shot or pellet-like, or even viscous liquid. When the drum is fill, the feed is diverted to an empty drum and the coke filled drum is steam purged and cooled with quench water. The drum is then drained of water and the top and bottom heads of the drum are removed for removing the coke from the drum. After the coke is removed, the drum is ready to be placed back in service to repeat the cycle.
How the coke is removed from the drum varies with the type and consistency of the coke. For example, solid coke may have to be drilled out whereas shot and liquid coke may fall out when the drum bottom head is removed. Even with steam purging and cooling with quench water, the coke is at a high temperature, typically exceeding 200 degrees Fahrenheit, when the drum heads are opened. The drum is also under pressure. When the drum is opened, hot steam and some hot coke typically pour out with force. For safety, the drum heads are opened remotely and the drum has a head or cover assembly suited for remote operation. An example of a suitable remotely operable vessel cover particularly useful for a coke drum is described in U.S. Pat. No. 5,221,019, assigned to Hahn and Clay in Houston, Tex.
In the typical coking process, the coke falling from the drum, or otherwise removed from the drum, goes into a chute where it is carried to a pit or other container for the coke. During the coking process, the opening to the chute is covered, typically with a cover, such as, for example, a grate, until the drum is ready for decoking. Removal of the cover is typically done manually. However, working in the vicinity of the bottom head of the coke drum is potentially hazardous. A typical chute can be many feet deep. There exists a need for safer processes that would not require manual removal of the chute cover.